Manipulation of ferroelectric and magnetic properties properties of single phase Bi4Ti3O12-3BiFeO3 solid solution through La substitution

TL;DR

This study explores how La substitution affects the structural, dielectric, ferroelectric, and magnetic properties of a Bi4Ti3O12-3BiFeO3 solid solution, revealing modifications in phase transitions and polarization behavior.

Contribution

It provides new insights into tuning the properties of Aurivillius compounds through La doping, highlighting changes in phase transition temperatures and ferroelectric/magnetic behavior.

Findings

Lattice parameters decrease with La substitution.

Ferroelectric transition becomes sharper with La doping.

Magnetization remains paramagnetic despite La doping.

Abstract

In this work, the potential to exploit Aurivillius higher order composition (n=6) given by Bi4Ti3O12-3BiFeO3 as single phase and high temperature magnetoelectric materials are well explored by elaborately studying the concerned structure and physical properties. Bi4Ti3O12-3Bi1-xLaxFeO3 (x=0, 0.01, 0.05, 0.1, 0.2) was synthesized via solid-state reaction route and X-ray diffraction data revealed that the lattice parameters associated with orthorhombic cell (space group P21am) decrease with increase in La3+ content confirming the incorporation of La. In the frequency dependent dielectric measurements, the ferroelectric to paraelectric transition temperature (Tc) corresponding to the parent (x=0) had two phase transitions vis., 803 K (broader) and 983 K (sharper) whereas phase transitions are single that progressively becomes sharper with increase in La substitution. Ferroelectric switching behavior (polarization (P) versus electric field (E)) was demonstrated for Bi4Ti3O12-3BiFeO3 and remnant polarization decreased significantly for La substituted compositions reflecting weaker ferroelectric ordering. In detailed Zero Field-cooled and Field cooled temperature dependent magnetization measurements, Bi4Ti3O12-3BiFeO3 exhibited Tc around 296 K. Though a marginal increase in the magnetization values for La substituted compositions (x=0.1 and x=0.2), the overall temperature dependent magnetization curves indicate overall paramagnetic nature. The results are more reflective of the switching off of the possibilities of long range ferromagnetic ordering with A-site rare earth doping in these Aurivillius layered compounds.